Conical scanning antennas were first applied in radar tracking of targets (the antennas acting both to transmit and to receive but generally scanning the transmitted beam). More recently, conical scanning antennas have been employed as ground station antennas for satellite telecommunication links tracking non geo stationary satellites.
A particular problem occurs when an antenna is mounted on a vessel at sea, since a vessel is subject to endless rolling, pitching and yawing motion due to the normal swells and tides and to the wakes of other passing vessels. It is not unusual for a small boat to roll through 50 to 60 degrees; the period of the roll is variable, but is on the order of ten seconds or so. The problem is of course exacerbated for smaller pleasure craft (which generally try to avoid extreme conditions).
For a water vessel (or other vehicle) to receive satellite communications it is therefore necessary that the receiver antenna be controlled to point at the satellite. Most seaborne satellite antennas are either gimballed or are mounted on drive motors which are responsive to sensors sensing the motion of the ship. An example of such an antenna is shown in EP0154240. Such arrangements are however mechanically complex and expensive. It is also known to mount an antenna on a gyro stabilized platform, but this limits the antenna size and weight since the capacity of such platforms are restricted.
Another problem with such arrangements is that the antenna is maintaining its orientation relative to the vessel or vehicle. However, when the vessel moves to a different geographical location, the relative inclination required to point at the satellite changes and consequently the antenna is mis-aligned.
These problems make such antennas unattractive for application as vehicle-borne receiver antennas for satellite television, where a simple, robust and inexpensive antenna is essential.